Spinnerette production method



July 3, 1962 J. A. CUPLER, l 3,041,894

SPINNERETTE PRODUCTION METHOD Filed Dec. 17. 1959 FIG 6 INVENTOR ATTORNEY @MWK" FIG. 5

FIG. 3

United States Patent Ofifice 3,041,894 Patented July 3, 1962 3,041,894 SPINNERETTE PRODUCTION METHOD John A. Cupier II, Cupler Drive-La Vale, Cumberland, Md. Filed Dec. 17, 1959, Ser. No. 860,152 7 Claims. (Cl. 76107) This invention relates to spinnerettes and a method of producing them.

As the trend continues towards higher temperatures and pressures in the production of synthetic fibers, it has become more difiicult to cope with erosion, corrosion and deformation of the spinnerettes employed in the extrusion of these fibers. It is known that certain stainless steels are highly resistant to corrosion and capable of being hardened to a high degree. However, there has been no known manner by which these characteristics could be employed in the production of spinnerettes. Accordingly, prior practice has relied upon softer materials through which the required orifices could be formed. These softer materials however, are subject to w'arpage and other types of deformation at the high pressures and temperatures encountered during extrusion. These softer materials also suffer through the scratching produced when their discharge surfaces are wiped for the removal of materials undergoing extrusion. It is not infrequent to encounter extrusion pressures of the order of 6000 lbs. per square inch and it is uncommon to find a spinnerette that will withstand such pressures for any extended period.

Thus, for a long time it has been desired to produce spinnerettes having the high corrosion resistance properties inherent to the so-called 430 and 316 stainless steels and at the same time achieving a hardness exceeding that possible with these alloys. The compositions of these alloys and others to be discussed can be found in available literature such as the catalogs of Latrobe Steel Company, Latrobe, Pennsylvania, and Crucible Steel Company of America, Pittsburgh, Pennsylvania.

It is among the objects of the present invention to provide a heat hardenable stainless steel spinnerette having high resistance to corrosion and a Brinell hardness number exceeding 250 and having a discharge surface intersected by a capillary extrusion orifice. The Brinell hardness number preferably exceeds 500 and preferably lies in the range between 500 and 80. The compositions preferred are martensitic such as those stainless steels known as 420 and 440. The spinneret-te contemplated by the present invention will ordinarily have an inlet surface intersected by a counterbore in communication with the orifice and in many instances, a single counter-bore will communicate with a plurality of such orifices.

The present invention also contemplates a method of producing stainless steel spinnerettes having high resistance to corrosion and a Brinell hardness number exceeding 250, comprising forming a capillary orifice through a surface of a heat hardenable stainless steel blank having an annealed Brinell hardness number below 250, and then beat hardening the blank to a Brinell hardness number exceeding 250. The capillary opening may be formed by drilling or punching to size. The capillary opening may be produced by forming it to a diameter below that ultimately required, and then after the hardening operation, enlarging the orifice to its ultimate size. The enlarging operation is preferably effected by removing material from the blank by cutting and/or abrading, following which the discharge surface of the spinnerette can be finished in accordance with known procedures such as those described in U.S. Patents Nos. 2,618,989, dated November 25, 1952 and 2,770,987, dated November 20,

A more complete understanding of the invention will follow from a description of the accompanying drawing wherein:

FIG. 1 is a sectional elevation of a spinnerette of the type contemplated;

FIG. 2 is a fragmentary sectional elevation of a spinnerette drilled with an undersize orifice in its annealed condition;

FIG. 3 is a fragmentary sectional elevation depicting the spinnerette of FIG. 2 after it has been heat hardened and had its capillary orifice drilled to ultimate size;

FIG. 4 is a fragmentary sectional elevation depicting the spinnerette of FIG. 3 having a plug inserted through the capillary orifice preparatory to finishing the discharge surface;

FIG. 5 is a fragmentary sectional elevation of the spinnerette of FIG. 4 with the plug removed after the discharge surface has been finished; and

FIG. 6 is a fragmentary sectional elevation of another form of spinnerette produced in accordance with the present invention.

The spinnerette 10 depicted in FIG. 1 contains a plurality of capillary orifices 12 intersecting the discharge surface 14 and communicating with counterbores 16 intersecting the inlet surface 18 of the body of the spinnerette. The blank from which the spinnerette 10 is formed is preferably a heat hardenable stainless steel having a high resistance to corrosion and a Brinell hardness number in annealed condition less than 250 and in hardened condition greater than 250. The hardened Brinell number preferably exceeds 500 and values up to 580 have been employed. Stainless steels of the martensitic types have been employed having the following compositions, given in percentages by weight:

resistance at their full hardness values and all of them have Brinell hardness values below 250 in annealed condition and above 250 after heat hardening.

' The blanks from which the spinnerettes are produced may be formed with their counterbores 16 and undersized capillary orifices 12 under annealed conditions as depicted in FIG. 2. The forming of the capillary orifice is preferably achieved by drilling.

Then the product is heat hardened whereupon the capillary orifice 12 is enlarged to its ultimate size. This enlarging operation is preferably performed by the removal of material utilizing a cutting and/or abrading operation to assume the form depicted in FIG. 3. Then the capillary orifice is plugged, as shown in FIG. 4 by the insertion of a plug 20, following which the discharge surface 14 will be finished in a suitable manner, as illustrated by the disclosures of Patents Nos. 2,618,989 and 2,770,987 previously mentioned. After removal of the plugs 20, the capillary orifice and its counterbore will assume the form depicted in FIG. 5. In this manner, any deformation of the spinnerette and its undersized capillary orifice resulting from the heat hardening treatment will be eliminated in the ultimate product. The enlarging operation being performed after heat hardening renders it possible to achieve a mirror finish on the capillary wall. The heat treatment may be performed in an inert atmosphere to enemas 3 eliminate scaling entirely, but at the temperatures required, ranging up to values approaching 2000 F., shrinkage and warping inevitably occur.

The spinnerette depicated in FIG. 6 of the drawing contemplates a plurality of capillary orifices 12 in communication with a single counterbore 16, exemplifying another form of spinnerette embodying the present invention.

Enlargement of the capillary orifices in the heat hardened spinnerettes can be effected with sintered carbide drills or reamers which are now available in the small sizes required for the extrusion of synthetic filaments.

The forms of the invention illustrated and described will suggest to those skilled in the art such modifications as fall within thescope of the appended claims.

I claim.

1. A method of producing stainless steel spinnerettes having high resistance to corrosion and a Brinell hardness number exceeding 250, comprising forming a capillary orifice through a surface of a heat hardenable stainless steel blank having an annealed Brinell hardness number below 250, and then beat hardening said blank to a Brinell hardness number exceeding 250.

2. A method according to claim 1 wherein said capillary orifice is formed by drilling.

3. A method according to claim 1 wherein said capillary orifice is formed with a diameter below the ultimate size required and is enlarged to its ultimate size subsequent to said hardening.

4. A method according to claim 3 wherein said opening is enlarged by removing material from said blank.

5. A method according to claim 3 wherein said opening is enlarged by a cutting operation.

6. A method according to claim 3 wherein said opening is enlarged by an abrading operation.

7. A method according to claim 3 wherein said surface is finished subsequent to the enlargement of said orifice.

References Cited in the file of this patent UNITED STATES PATENTS 1,654,936 Jones Jan. 3, 1928' 2,618,989 Cupler Nov. 25, 1952 2,671,297 Arms Mar. 9, 1954 2,770,987 Cupler Nov. 20, 1956 2,891,278 Cook June 23, 1959 2,904,828 Smith Sept. 22, 1959 

